The present invention relates generally to control circuits and, more specifically, to situations in which one of two control circuits may be selected to control a single controlled system. The optimal control circuit for a controlled system, such as a power supply, may depend on the conditions under which the controlled system is operating. Rather than develop two control circuits and manually switch between them, it is desired to monitor the controlled system and switch between the control circuits based on the monitored state.
This desire has been frustrated by the fact that the output of an unused control circuit does not necessarily track the active control circuit. Therefore, when control is switched between the circuits, the controlled system can be disturbed in an undesirable manner during the transition.